RECOVERY OF RARE EARTHS AND SCANDIUM FROM URANIUM LEACHATES

Ural Federal University

Physical Technology Institute

The Department of Rare Metals and Nanomaterials

SCALE Scandium-Inventory Workshop – 27/11/2018

Ural Federal University

Today:

• Top 500-550 in QS World University Ranking

• Top 10 in Interfax Russian national ranking

• The 4th among Russian universities by the

number of the articles published in

internationally recognized

scientific journals

UrFU is situated on the border of Europe and Asia

Institute of Physics and

Technology (PhysTech)

Research Priorities:

• Chemistry of Rare and Radioactive Elements

• Atomic Eneregtics Modernization (research of a

closed fuel cycle with salt and metal melts based

generators of 4th generation)

• Nanomaterials for Solar and Hydrogen Energy

• Radiopharmaceuticals for Cancer Diagnostics and

Therapy

The border between Europe and Asia

The technology of recovery REE and scandium as by-products to

uranium ISL

The technology of extraction REE from apatite and

phosphogypsum

Main recent achievements

JSC Dalur is located in the Dalmatovsky District of Russia’sKurgan Region. The company conducts commercial development of deposits in the Trans-Ural Uranium-Ore Area (Dalmatovskoye and Khokhlovskoye). JSC Dalur produces uranium by downhole in-situ leaching method.The company’s finished product is concentrate of natural

uranium (yellow cake).

Concentrations:

•REE– 30 mg/l

•Sc – 0.8 mg/l

JSC Khiagda is located in the Bauntovsky District of the Republic of Buryatia. The company develops the deposits of the Khiagdinskoye ore field.Test uranium mining with the use of in-situ leaching method began in 1999.Productive solutions are processed into the end product —concentrate of natural uranium (yellow cake).

Concentrations:

•REE – 60 mg/l

•Sc – 0.5 mg/l

LREE HREE

70 30

LREE HREE

70 30

The distribution of lanthanides in solution ISL uranium The distribution of lanthanides in solution ISL uranium

10-15% scandium oxide concentrate and 85-90% REE concentrateCarbonate REE concentrate and its activity rate

№ Element , % № Element , %

1 Li 0,0007 26 Zr 0,0083

2 Be 0,0029 27 La 7,7836

3 B 0,0203 28 Ce 22,3859

4 Na 0,2442 29 Pr 3,3187

5 Mg 0,0536 30 Nd 11,6157

6 Al 0,6719 31 Sm 1,9142

7 P 0,1306 32 Eu 0,4196

8 K 0,0583 33 Gd 2,4324

9 Ca 0,2452 34 Tb 0,2170

10 Sc 0,0202 35 Dy 2,7096

11 Ti 0,0022 36 Ho 0,0713

12 V 0,0005 37 Er 0,1224

13 Cr 0,0084 38 Tm 0,0060

14 Mn 0,0086 39 Yb 0,0476

15 Fe 0,0885 40 Lu 0,0059

16 Co 0,0003 41 Th 0,0004

17 Ni 0,0044 42 U 0,0084

18 Cu 0,0051 43 Σ REE 54,2757

19 Zn 0,0436

activity concentration 5,8±0,9·106

Bq kg-1

20 Ga 0,0207

21 Ge 0,0331

22 Se 0,4656

23 Rb 0,0002

24 Sr 0,0012

25 Y 1,2257

REE concentrate activity is basically caused by Ac-227 and its decay products.

- It occurs in uranium and thorium ores

- One tone of natural uranium contains only 6*10-5 gram of actinium

- To produce 1 gram of actinium you need to recycle 16,000 tons of uranium, (or 1000 wagons)

Uranium-235 decay chain

Methods of REE and Ac separation

Chromatographic actinium separation

from REE:

It is based on the ionic radius difference

For this aim complexation ionic exchange chromatography is used with organic acid or salts solutions (citrates, lactates, etc) as eluents

In this case Actinium is eluted last

Actinium has a similar chemical behavior as REE (La, Ce and others)

Extraction method of actinium separation

from REE :

It is based on the extraction coefficients difference

Tributyl phosphate (TBP, phosphoric acid ester) (C4H9O) 3P = O is used to remove Actinium from low pH solutions in a significant amounts of salting-out agents presence (ammonium nitrate, aluminum and others)

Also TTA (tetradecylthioacetic acid) is used to separate actinium from radium and its decay products as TBP

REE recovery mini-pilot test

Developed deactivation technology was tested

under industrial conditions at the uranium

mining plant. Approximately 100 g of the REE’s

concentrate with high activity was treated;

after deactivating it was about 90 g of REE’s

concentrate with activity concentration of

(1-5) × 103 Bq kg-1.

Uranium sorption column 50 m3

REE deactivation column 15 dm3

Prospective industrial sources of scandium in Russia

Source Sc content

Uranium leach liquors (ULL) <1 mg/l

Hydrolytic waste acid after production of TiO2 ~20 mg/l

Red mud (bauxite treatment waste) 0.007–0.011%

Coal ash 0.006-0.012 %

Uranium ores Up to 0.002%

Tungsten ores 0.01–0.1%

Ion exchange resins for preliminary scandium separation

Purolite S-950

Lewatit TP-260

Tulsion CH-93

ЭКО-10

Aminomethyl phosphonic ampholytes

Polyfunctional ion exchange resin

Purolite S-957

Characteristics of Sc sorption from ULL by various IEX Resins

Element Sc Th Al Fe Ti U

Capacity, mg per g of resin

0.28 0.58 7.41 3.21 1.38 0.38

Full dynamic exchange capacity

Tulsion CH 93

ElementAl Ca Sc Fe Th U

Capacity, mg per g of resin

26.43 4.5 0.65 60.67 1.09 0.43

Purolite S-957

The dynamics of Sc sorption

Dynamics of elements sorption by Purolite S-957

Kd Sc/Th=1.14

Kd Sc/Th=1.41

Characteristics of Sc sorption from ULL by various IEX Resins

Purolite АА-03 Dynamics of elements sorption by Purolite АА-03

IR spectra of Purolite S-957, S-950 and АА-03

in H+ form

IR spectra of Purolite S-957, S-950 and АА-03

in Sc3+ form

Element Al Ca Sc Fe Th UCapacity,

mg per g of resin

10.14 0.27 0.37 15.47 0.14 0.44

0

0,2

0,4

0,6

0,8

1

1,2

1,4

0 20 40 60 80 100 120

С/С

0

V/Vкол

Al

Ca

Sc

Fe

Y

Mo

Th

U

Ti

Kd Sc/Th=6.28

40

0

60

0

80

0

10

00

12

00

14

00

16

00

Пр

оп

уска

ни

е, %

V, см-1

S-957

S-950

AA-03

40

0

60

0

80

0

10

00

12

00

14

00

16

00

Пр

оп

уска

ни

е, %

V, см-1

S-957

S-950

AA-03

Radioactive contaminants in the primary scandium concentrate

0

3000

6000

9000

12000

15000

18000

0 50 100 150 200 250 300 350 400 450 500

E, keV

Co

un

ts

0

10

20

30

40

50

60

70

80

2000 3000 4000 5000 6000 7000 8000

Co

un

ts

Е, keV

Gamma spectrum of the Sc concentrate Alpha spectrum of the Sc concentrate

Radioactivity of the Sc concentrate is conditioned by presence thorium-234 (half-life is 24

days, beta and gamma emitter) and thorium-230 (half-life is 80,000 years, pure alpha

emitter). Activity was up to 108 - 1011 Bq/kg depending on the resin type being used for

scandium separation.

Sc/Th separation is necessary

Scandium recovery mini-pilot test

The results of work of the mini-pilot test

Compound % wt. Compound % wt.Sc 30.09 Cl 0.063Na 9.61 K 0.049Al 3.29 Sr 0.007

Mg 0.78 P 0.005Ca 0.65 Y 0.004Fe 0.12 Zr 0.003Si 0.08 Th 0.003S 0.070 Ni 0.001

Composition of the scandium concentrate obtained at the mini-pilot test

Scandium recovery pilot scale plant (200 m3 of ULL per hour)

The results of work of the pilot scale plant

Composition of the scandium concentrate obtained at the pilot scale plant

Compound % wt. Compound % wt.ScF3 98.040 Y2O3 0.037FeF2 0.395 CeO2 0.009SO3 0.355 Pr6O11 0.006NaF 0.340 Nd2O3 0.004AlF3 0.298 V2O5 0.003

Si 0.131 ThO2 0.002C 0.085 ZrO2 0.002

MgF2 0.080 SrO 0.002CaF2 0.058

Vielen Dank für Ihre Aufmerksamkeit!

Thanks for Attention!